Diamond core drilling equipment is used extensively to drill circular or annular holes in a variety of material. Annular holes are formed in concrete, asphalt, rock and related materials for a variety of reasons. For example, holes are drilled in concrete for the purpose of correcting the settlement of pavement. Such settled concrete pavement is customarily restored to proper position by boring holes into the pavement and packing mud therethrough and beneath the pavement in order to raise and restore its level position. Further, for example, holes are also commonly drilled in concrete and similar materials so as to provide openings to utility conduit cells located beneath the surface of cast concrete floors of office and factory buildings. Further, for example, holes are also commonly drilled in concrete or masonry to facilitate the mounting of objects such as posts or pipes.
Generally speaking, diamond core drilling equipment comprises a motor-driven core drill assembly and a core drill bit or hole saw. The core drill assembly may embody various configurations, but such assembly generally comprises a base and a guide column extending up from the base. A carriage is provided between the column and the motor for guiding the motor along the column. Mounted to the motor is the drill bit. U.S. Pat. No. 3,464,655 to Schuman is an example of a prior art core drill assembly.
The prior art provides various types of core drill bits or hole saws. However, the majority of the commercial bits used today have cutting heads formed of a diamond impregnated material. More particularly, the cutting head comprises a plurality of cutting segments or teeth mounted at the distal end of the cylindrical body of the bit. Each of the segments includes a uniform concentration of diamond particles dispersed throughout the segments. Examples of prior art diamond core drill bits or hole saws are shown in a promotional brochure entitled "Laser Welded Dry Diamond Hole Saws For Brick And Block" distributed by Diamond Products of Elyria, Ohio, and dated Jan. 1, 1988.